The goal for this project was to develop a tilt-in-space wheelchair that could be used and built in Tanzania by Kyaro Assistive Technologies for under $70. A tilt-in-space wheelchair allows the user to recline, for this project, up to 45 degrees, without the center of gravity moving enough to make the chair unstable. The tilting function is important for users where spinal compression needs to be limited or actions like swallowing are difficult. 
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Most available tilt-in-space wheelchairs cost easily over $1000 and require lots of high-end machinery to fabricate. For this project, the budget was limited to $70, and machinery was limited to hand tools, a drill press, and stick and MIG welders. For our prototype, we chose to use a four-bar slider linkage. This allowed us to keep the movement of our center of gravity minimal without the complex geometries typically used in tilt and space wheelchairs. When deciding on the lengths of our linkages, we used MATLAB to simulate the sliding motion and then parameter swept through our possible linkage lengths to determine the lengths that minimized the movement of our center of gravity(Figures 1 & 2). 
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Using Tanzanian stock pricing, we were able to build our wheelchair for $44.84. More details about the project can be found on the project website here. 

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Working under a tight budget and with limited tooling was a fun challenge and created lots of areas for problem solving. For this project, I focused on using analysis to reinforce my design and find redundancies in our design to lower cost and weight. I was also focusing on designing for manufacturability, specifically minimizing the importance of tolerancing, as the stock in Tanzania has much more variance than it does in the US.